Notice: This project page is no longer being updated as of January 2023.
Nurseries and greenhouses are intensive production spaces where careful water management is critical to business.
As the climate changes, there will be more periods of hot and dry weather in the region. Efficiently managing water resources will be essential to maintaining water security in the future. University of Maryland researchers are studying the benefits of using a soil moisture sensor network to manage water in nursery and greenhouse operations. The sensors can help to optimize water usage by precisely scheduling how much water is applied to plants through the drip and spray irrigation systems. This practice can ensure that plants receive the appropriate amount of water and are only watered when needed. Avoiding overwatering is important, as this can limit the amount of nutrients that leach from containers. Less leaching reduces fertilizer costs and decreases runoff, which protects water quality in local waterways. Reducing water usage will provide additional cost savings to farmers who have to pay for their water. Soil moisture sensors can help farmers use water resources in a more efficient and effective manner.
“Water security is very much tied in with climate change. What we are finding is that our well capacities are typically low in the piedmont areas anyway, and quite frankly, with increased urbanization and increased heat in the summer, we are being a lot more careful in how we manage our water resources, and groundwater resources in particular. So, being able to capture and recycle water is incredibly important for growers who use irrigation because it (is) all about water security.”
- Dr. John Lea-Cox, Professor and Extension Specialist, University of Maryland
Catoctin Mountain Growers is a family-owned business located in Keymar, MD. The nursery grows annuals, perennials, and specialty plants, including mums (chrysanthemums), and poinsettias. Chrysanthemums are a fall favorite in the United States, with millions of these potted plants sold across the country each year. These colorful mums are stacked up and ready to be shipped out to a retailer contracted with Catoctin Mountain Growers. Growing space totals more than 25 acres, with over 15 acres in a glass greenhouse. The Van Wingerden family has owned and managed the nursery for over 32 years. They embrace the use of innovative technologies and cutting-edge growing strategies to produce high quality plants. Currently, the operation is working with Dr. John Lea-Cox, to improve their water use efficiency. Dr. Lea-Cox is a Professor and Extension Specialist at with the University of Maryland who works with the nursery and greenhouse industry.
Want to see what a 15-acre greenhouse looks like from above? Check out the scale of Catoctin Mountain Grower's greenhouse by watching this drone footage from SBI Software. SBI is a software tech company that supports the nursery industry.
New irrigation practices are being explored at Catoctin Mountain Growers. The research is part of the Specialty Crops Research Initiative – Managing Irrigation and Nutrients with Distributed Sensing (SCRI-MINDS) project. "Saving water, increasing efficiency and reducing the environmental impacts of ornamental plant production practices" is the main goal of SCRI-MINDS. Critical to achieving this goal is the use of wireless sensor networks. The sensors allow growers to monitor soil moisture in plant containers or fields so they can control the application of water and nutrients. Dr. John Lea-Cox provides more details on the SCRI-MINDS project. Here he focuses on how soil moisture sensor networks can enhance water management in nursery and greenhouse operations.
The SCRI-MINDS researchers believe that “water management is the most important crop production issue in nursery and greenhouse systems.” Plant growth and development, as well as a plant's use of energy, fertilizers, pesticides, and herbicides, all depend on water. In a greenhouse system, ornamental plants are typically grown in soilless substrates, such as pine bark and peat, which do not retain a lot of water. Because container plants often have a small soil volume with large canopies, they require frequent irrigation throughout the growing season. (In the Northeast, the growing season typically runs from March through November.) SCRI-MINDS researchers are trying to optimize plant growth while minimizing nutrient leaching from irrigation. Their goal is to produce a high-quality product with little to no environmental impact. Currently, 2 of the 10 acres of outdoor fields at this operation are equipped with soil moisture sensors.
Technologies and software for irrigation management developed as part of the SCRI-MINDS project are now commercially available. Anyone can use these advanced wireless control technologies, but there is a learning curve. Because irrigation systems can be highly variable, it is important to understand how your system works. This will help you make good management decisions when using a soil moisture sensor network. One of the trickiest things to figure out is where to place the monitoring nodes (see the mums with the orange flags below). Nodes need to be positioned in such a way that they adequately represent the conditions across an entire field of plants. The best advice project researchers have for new adopters is to start small!
The Catoctin Mountain Growers want to be good stewards who use water efficiently and effectively. The water demands of their operation can reach 250 gallons per minute during peak periods. By using a closed watering system, they can capture runoff to reuse for watering plants. Dr. John Lea-Cox, Professor and Extension Specialist from the University of Maryland, is working with the operation. Here Dr. Lea-Cox explains the need for a holding pond and how the pond helps to protect the operation’s water supply and provide water security.
Dr. John Lea-Cox discusses the water quality issues that need to be considered when using recycled pond water to irrigate plants.
Sensor networks have the potential to improve water quality and increase the amount of available water for an operation. At Catoctin Mountain Growers, water usage has decreased by 10–12% as a result of better irrigation practices. Researchers believe water use can be reduced even more, perhaps by as much as 50%. In a nursery or greenhouse operation, nutrient management is tied to water management. Simply put, if you avoid overwatering, then you can reduce nutrient leaching from plant containers. This can reduce fertilizer use and help to minimize the risk of unintended nutrient losses into local waterways. Check out these resources to learn more about some hardware and software tools that can help farmers use sensor-based strategies to adapt to climate change:
"Climate Change and Agriculture in the Northeast: Teamwork, Responses, and Results," an article featuring a section on water conservation with farm smart sensors.
"Advancing Wireless Sensor Networks for Irrigation Management of Ornamental Crops: An Overview," a 2013 publication by Lea-Cox and others in American Society for Horticultural Science.
This weather station collects data that helps growers and researchers understand the microclimatic conditions of their site. Weather parameters measured here are entered into sensor software programs. The programs function as predictive models to help growers make better management decisions. The weather data can also be used to calculate growing degree days, insect emergence rates, bud and flower emergence, and disease outbreaks. This type of information can improve the timing and use of pesticides, enable pollination decisions, and guide plant watering regimes. Having the data to make informed decisions can lead to enhanced productivity and profitability.
Dr. John Lea-Cox is a Professor & Extension Specialist at the University of Maryland. Here he demonstrates how to place a sensor into a container that will monitor soil moisture in a greenhouse.
Commercial greenhouse operations are very intensive environments where production can ranges from 1 to 3 million plants per acre each year. Different methods of irrigation can be used within a greenhouse. Hand irrigation, stationary sprinklers, and drip, boom, or flood systems are all methods used at Catoctin Mountain Growers. So far, Dr. John Lea-Cox has equipped about 1 acre of the 15 acres inside this greenhouse with his soil moisture sensor network.
Boom irrigation provides a way to uniformly water plants in a greenhouse. This commonly used system consists of one or more pipes with nozzles attached that spray water as the system moves over the plants. One disadvantage of this type of irrigation is that the leaf surfaces get wet, which can lead to disease.
You might think the glass walls and ceiling transmit enough sunlight to keep the greenhouse toasty warm, but maintaining optimal temperatures for growth can sometimes be a challenge. Heat is added to this greenhouse by pumping hot water through pipes that run under the cement floors. Three boilers run 24 hours a day to heat water stored in this 2 million gallon tank. The largest boiler runs on animal fat, while the other two run on oil and propane. The Van Wingerden family reports that they are thinking about transitioning to a biomass boiler to reduce their carbon footprint.
Cooling a greenhouse can be even more of a problem than heating it. When ventilation alone does not provide the necessary cooling, adding shading can help reduce the temperature. A number of approaches can be used to shade a greenhouse. Compounds can be rolled, brushed, or sprayed onto the glass, or fabric and other types of materials can be installed. Here, shade cloth is used to moderate temperatures in the greenhouse.
This versatile greenhouse has roof vents that can open to increase ventilation on high heat days. Because temperature impacts plant health, it is important to know when to air out a greenhouse.
Catoctin Mountain Growers uses flood irrigation to water plants in some of their greenhouse bays. For a flood system to work, the floors must be level. Water is pumped up through the floor and brought to a level that wets the base of the plant container but not the foliage. By keeping leaf surfaces dry, disease potential can be greatly reduced. The water is then drained away so that the roots receive air for healthy growth. To see how it all works, watch here as a bay fills with water through the flood irrigation system.
Flood irrigation has its benefits, but it is water intensive and essentially treats all of the plants the same. Each plant receives the same amount of water, so using soil moisture sensors with this type of irrigation would not provide any water saving benefits.
Optimizing water quality optimizes plant health. Good filtration reduces disease pressure and decreases labor costs related to irrigation system maintenance. Testing the water alkalinity is also important. If the water alkalinity is too high, it can eventually increase the pH in the substrate. This can lead to deficiencies in certain essential micronutrients like iron and manganese. Catoctin Mountain Growers currently uses glass filters and an acid injection system to help control the alkalinity of their water.
This pump and filter station delivers water to the greenhouse and outdoor container fields. After water is pumped through sand filters, chlorine is added to help control pathogens in this closed watering system. Having an adequate water supply from a secure source is critical to the success of the greenhouse operation. Many factors must be considered when determining the type and size of pump and filter system needed for a greenhouse.
In the bays with flood irrigation, soluble fertilizers can be injected into the water as it rises up from the floor. Through this technique, called fertigation, plants are fertilized through irrigation. Nutrient solutions for individual elements like nitrogen, phosphorus, and potassium can be added. By using separate solutions, desired nutrient ratios can be maintained. The water used in this process is recycled, so there is no risk of negatively impacting local natural waters with nutrient-rich runoff.